<!-- "none" is a legitimate description when the title is already adequate; see WP:SDNONE -->
The 1984 Pacific hurricane season featured numerous tropical cyclones, several of which were impactful to land. It was a busy hurricane season with 21 named storms, 13 hurricanes, and 7 major hurricanes, the latter of which are Category 3 or stronger cyclones on the Saffir–Simpson scale. The season also had an above-normal accumulated cyclone energy (ACE) rating of 193.7, despite the presence of a La Niña event, which typically results in less activity, and had the second-most storms for a La Niña year on record, largely due to average sea surface temperatures across the Eastern Pacific. Seasonal activity began on May 17 and ended on November 8. This lies within the confines of a traditional hurricane season which begins on May 15 in the East Pacific and June 1 in the Central Pacific, and ends on November 30 in both basins. These dates conventionally delimit the period during each year when most tropical cyclones form.
The drought-stricken Hawaiian Islands received beneficial rainfall from Hurricane Douglas in July and Tropical Storm Kenna in August. The remnants of hurricanes Iselle, Marie, Norbert, and Odile all contributed to enhanced precipitation across the Southwestern United States during the season, including snowfall in higher elevations; flash flooding killed one person in Texas. Hurricane Lowell attracted widespread coverage for damaging the Blue Falcon and forcing the rescue of its 23 crewmembers. In September, torrential rains from Hurricane Odile in Southern Mexico severely damaged crops, inflicted water damage to about 900 homes, and left thousands of residents displaced or without normal services. The storm killed at least 21 people. Multiple hurricanes contributed to rough surf along the California coastline, resulting in one death and hundreds of water rescues.
Systems
Tropical Storm Alma
On May 13, an area of disturbed weather within the Intertropical Convergence Zone (ITCZ) crossed Panama and Colombia into the East Pacific. Strong westerly wind shear inhibited this disturbance initially, but atmospheric conditions improved over subsequent days, allowing it to become the season's first tropical depression around 18:00 UTC on May 17. The system increased rapidly in size as developing high pressure to its north brought it over very warm ocean waters.
Hurricane Elida
A tropical disturbance formed south of Salina Cruz, Oaxaca, on June 26 and was upgraded to a tropical depression around 00:00 UTC on June 28. Some street flooding was reported in Acapulco, Guerrero. Farther north in western Texas, moisture from Iselle collided with cooler air from the north, causing thunderstorms and heavy rainfall. Up to fell in El Paso. Flash flood watches had been hoisted across several counties, and minor street flooding was reported in both El Paso and Juarez. Some mountain roads were impassable. A girl was killed when her normally dry home in a creekbed was overwhelmed by a flood. One person was also injured by lightning. At beaches in Orange County, California, waves up to necessitated numerous lifeguard rescues. Some 385 rescues occurred in Newport Beach, while an additional 50 people were saved at San Clemente; rescues more than tripled the average at Huntington Beach.
Tropical Storm Julio
At 00:00 UTC on August 15, a new tropical depression formed south of Acapulco. High pressure, extending across Mexico from the Gulf of Mexico, directed the system west-northwest.
Tropical Storm Moke
In August 1984, expansive ridging persisted across the North Pacific while a series of cold-core lows wandered underneath. One such upper low persisted near the International Date Line in close vicinity to Midway Island—as evidenced by low temperatures aloft in radiosondes released there—and developed a surface circulation, being declared as a tropical depression by the Japan Meteorological Agency on September 2. While the lack of satellite coverage made tracking the system difficult, Humidity from the storm spawned swift-moving thunderstorms across southern California. The roof of a bowling alley collapsed, submerging bowling lanes in of water. Floods inundated roads, including U.S. Route 95 in California, and frequent lightning caused power outages to dozen of homes.
Hurricane Norbert
At 18:00 UTC on September 14, the season's next tropical depression developed southwest of Baja California. It strengthened into Tropical Storm Norbert six hours later. Embedded within weak steering flow, the newly named cyclone wound its way north, particularly after upper-level trough developed over the Rocky Mountains. Between 00:00–06:00 UTC on September 26, Norbert made landfall near Punta Abreojos as a tropical storm. While the storm is officially recognized as dissipating over Baja California, forecasters in Arizona expressed high confidence that it remained a tropical cyclone into that state.
In the small fishing communities of Punta Abreojos and La Bocana along the coastline of Baja California Sur, 90 percent of structures were demolished. One person was killed, one person was reported missing, and more than $140 million in damage occurred there. The remnants of the cyclone produced sporadic rainfall across Mexico. Slightly higher accumulations were reported in Arizona, where flash flood watches were hoisted across several counties and some school districts released students early owing to those concerns. Accumulations peaked at on Kitt Peak in Arizona. Between the Zihuatanejo and Acapulco airports, some 87 commercial flights were cancelled, including 50 charter flights. Hotels were deserted across typically busy tourist areas. The heavy precipitation inundated roadways and filtered into the lobby of the Zihuatanejo airport. Throughout the state of Guerrero, 44 riverbank and mountain communities were isolated, encompassing some 30,000 residents. The cyclone overturned a barge on the Atoyac River, resulting in the drownings of 18 passengers and 3 crewmembers. Odile compounded the effects of previous systems which in totality yielded Mexico's wettest year since 1978. Those floods damaged countless structures, severely affected crops, left thousands of residents displaced, and killed many people.
Hurricane Polo
An area of disturbed weather entered the Gulf of Tehuantepec on September 24, organizing into a tropical depression by 00:00 UTC on September 26. The depression moved west-southwest initially, but it curved northwest after becoming Tropical Storm Polo around 18:00 UTC on September 28. Heavy rain across Colorado translated to snow in higher elevations, with advisories warning of the potential for accumulations.
Tropical Storm Rachel
A tropical disturbance crossed Costa Rica on October 4. It remained steady state for several days while moving west but ultimately organized into a tropical depression around 18:00 UTC on October 7. The depression encountered warm waters along its track, This was a new set of names, and every name used this season was used for the first time. No names were retired from this list following the season, and it was next used (expanded to include "X", "Y", and "Z" names) for the 1990 season.
{| width="90%"
|
- Alma
- Boris
- Cristina
- Douglas*
- Elida
- Fausto
- Genevieve
|
- Hernan
- Iselle
- Julio
- Kenna*
- Lowell
- Marie
- Norbert
|
- Odile
- Polo
- Rachel
- Simon
|}
For storms that form in the North Pacific from 140°W to the International Date Line, the names come from a series of four rotating lists. Names are used one after the other without regard to year, and when the bottom of one list is reached, the next named storm receives the name at the top of the next list.
